Chemist who shared 2001 Nobel Prize dies at 95

ST. LOUIS -- William S. Knowles, a retired Monsanto Co. organic chemist who shared a Nobel Prize for helping to solve a vexing problem in the manufacture of medicines, died Wednesday of complications of ALS at his home in Chesterfield, Mo. He was 95.

Knowles worked for Monsanto from 1942 until 1986. In 2001, he shared the Nobel Prize in chemistry with two other scientists.

From 1968 to 1972, Knowles led development of a chemical catalyst to create safe compounds for producing L-Dopa, a drug for treating Parkinson's disease.

After the award was announced, Monsanto praised Knowles for research "that changed the face of modern medicine."

His work concerned a problem of long standing in organic chemistry. Some molecules exist in two mirrorimage forms, called chiral forms, that can have markedly different and dangerous effects. One example was thalidomide, a drug developed in the 1950s to ease nausea in pregnant women. It did, but it also caused deformities. Knowles' group at Monsanto developed a way to safely remove the dangerous molecular forms.